Application of Cloud Point Extraction for Copper, Nickel, Zinc and Iron Ions in Environmental Samples

A cloud point extraction procedure was presented for the preconcentration of copper, nickel, zinc and iron ions in various samples. After complexation by 2-(6-(1H-benzo[d]imidazol-2-yl)pyridin-2-yl)-1H-benzo[d]Imidazole (BIYPYBI), analyte ions are quantitatively extracted in Triton X-114 following centrifugation. 1.0 mol L(-1) HNO(3) nitric acid in methanol was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for BIYPYBI, Triton X-114 and HNO(3) and bath temperature, centrifuge rate and time were optimized. Detection limits for Cu(2+), Fe(3+), Zn(2+) and Ni(2+) ions was 1.4, 2.2, 1.0 and 1.9 ng mL(-1), respectively. The preconcentration factors for all ions was 30, while the enrichment factor of Cu(2+), Fe(3+), Zn(2+) and Ni(2+) ions was 35, 25, 39 and 30, respectively. The proposed procedure was applied to the analysis of real samples.